Automatic lathe



June 26, 1945. w. F. GROENE ETAL 2,379,147

AUTOMA'I'I G LATHE Original Filed June 20, 1942 6 Sheets-Sheet 1 FIG. I.

INVHVTORJ WILURM F. GROEHE, Y RRTHUR W. HUFDERHRK Min Am RME vs Jlme26,1945- w. F. GROENE ET AL AUTOMATIC LATHE 6 Sheets-Sheet 2 Original FiledJune 20, 1942' llllllllllllllllllllllllllll so In INVENTORS \LLRN F.GRDENE. BY ARTHUR .RUFDERHRR.

ATTORNEY;

June 26, 1945. w. F. GROENE ETAL AUTOMATIC LATHE 6 Sheets-Sheet 3Original Filed June 20, 1942 FTE, ]]I

IN VEN TORS MLURM F. GROENE,

'rromveys June 26, 1945. GROENE ETAL 7 2,379,147

AUTOMAT I C LATHE Original Filed June 20, 1942 6 Sheets-Shget 4INVENTORS \MLUPM F. GROENE.

. wn w RR'THUR W. RUFDERHRR,

[III] I l I ll! IIIlll ATTORNEYS June 26, 1945- w. F. GROENE ETALAUTOMATIC LATHE Original Filed June 20, 1942 6 Sheets-Sheet 5 INVENTORSMLLJRM F. GROENE, BY HRTHUR wamwaanm,

FIG. Y

June 26, 1945. w. F. GROENE ET AL AUTOMATIC LATHE Original Filed June20, 1942 6 Sheets-Sheet 6 INVENTORS \MLU PM F. GROENE,

RRTHUR N. RUFDERHRR,

ATTORNEYS ing and unloading.

Patented June 26, 1945 AUTOMATIC LATHE William F. Greene and Arthur W.Aufderhar, Cincinnati, Ohio, assignors to The R. K. Le Blond MachineTool Company, Cincinnati; Ohio, a corporation of Delaware Originalapplication June 20, 1942, Serial No.

447,810. Divided and this application Novemher 6, 1944, Serial No.562,080

8 Claims.

This invention relates to multiple spindle lathes wherein a plurality ofworkpieces are simultaneously turned to duplicate form. It is known inlathes of such type, to mount the tailstocks on slides extending at anangle to the work axes, and to provide mechanism for so sliding thetailstocks out of their work position to permit the workpieces to beloaded into the lathe in an axial direction. Such machines, whilemechanically sound, require expensive complications in the slides andoperating mechanism therefor. Our invention provides a multiple-spindlelathe which, while retaining all the advantages of axially-loaded lathesof the type aforesaid, eliminates numerous parts previously deemednecessary and turns out work of a very high degree of accuracy while, atthe same time, saving large amounts of time by providing clear andunobstructed passageways through the lathe for load- While the inventionis perhaps best illustrated and may find its greatest usefulness inconnection with center-drive lathes, it is not so limited, but isequally applicable in multiple-spindle lathes using conventional head-'stocks and tailstocks.

It is an object of our invention therefore, to provide a multiplespindle lathe with tailstocks sliding in an axial direction only, thatmay be loaded in an axial direction.

It is another object to provide a lathe as in the preceding paragraph,having two tailstocks and center drive chucks, that may be loaded fromeither end.

It is a further object to provide a lathe with loading openings orapertures between'adjacent tailstocks through which workpieces may bepassed into the lathe without any substantial angular movement thereof.

A further object is to so correlate the tool blocks and means forcarrying them, with loading openings in the tailstocks, as to providefree, unobstructed loading passageways through the lathe when the toolblocks are in retracted or idle position whereby efficient andtime-saving loading and unloading of the lathe are assured.

' It is a further object of our invention to provide a carrier for thetool blocks offset from the work axes and whereon each block is locatedbeneath a corresponding work axis defined by a pair of spindles, thetool blocks being spaced vertically to provide openings therebetween inalignment with corresponding loading openings in the tailstocks when theblocks are in idle position.

Other objects and advantages of our invention will appear as thedescription proceeds.

Inthe drawings:

Figure I, is a front elevational view of the multiple spindle centerdrive lathe of this invention, particularly showing the location of thecenter drive work spindle housing, the end tailstock housing, theloading passageways through the tailstock housing for axial insertion ofthe work pieces in' the center drive chucks on the work spindle, andalso showing the swinging facing tools mounted on the tailstock housing.

Figure II, is a rear elevational view of the machine shown in Figure I,particularly showing the main drive motor for rotating the workspindles, the tool relief cam mechanism for the turn ing tool slides,and the fluid pressure actuating cylinders for operating the centers inthe left hand tailstock Figure III is a. vertical transverse sectionshown on the line III-III' of Figures I, II, and IV, particularlyshowing the relationship of the turning tools on the turning tool slide,the taper attachment mechanism of the turning tool slides, and theswinging facing tools mounted on the tailstock housing.

of Figures I, II, and IV, particularly showing the rack and pinionactuating mechanism for effect-. ing the turning feeding movement forthe turning tool slide, and 4 Figure V1 is an enlarged diagrammaticview' of the feeding mechanism for the turning tool slides. Referringnow to the drawings in which like reference numerals identifycorresponding parts throughout, the numeral I indicates a base uponwhich is mounted a frame 2 (Figures I, II and V). A work spindle housing3 is fixed to frame 2 and .in the particular machin shown, this housingis of the center drive type. Thus there are provided a tailstock housing4 at the left as viewed in Figure I, and a second tailstock housing 5 atthe right. I

Drive housing 3 has vertically aligned work spindles 6, 1, 8 journaledtherein. Each spindle carries conventional chucking devices 9 wherebythe work is gripped and rotated as the spindles are turned. This turningis effected by ring gears.

Ill, H, and i2 (Figure III), connected by 'idlers l3 and I4 so that allof the ring gears rotate synchronously in the same direction. Thelowermost ring gear |2 meshes with an idler gear I5, in turn driven by apinion IS on a main drive shaft IT. This drive shaft l1 carries a maindrive pulley 8 which is driven by belts l9 from the main drive motor 20.

Tailstock barrels 2| are mounted in the left hand tailstock 4. Eachbarrel carries a work center 22, 23 and 24, respectively, and eachbarrel is adapted for actuation by conventional screw means havingsquared heads 25 whereby the centers may be properly adjusted to engagecenter holes in the ends of the workpieces W.

The right hand tailstock'ihas similar axially reciprocable barrels 26having centers 26a and being actuated by individual hydraulic mechanismseach comprising a hydraulic cylinder21 (Figure II) having a piston 28therein. Each piston operates a rod 29, the free end of which isconnected to one end of a lever 30. (See also Figure IV.) Each lever ispivoted at its central part on frame 2 and, at its other end, to a.respective one of barrels 26. Fluid pressure connections not shown leadto each cylinder, on opposite sides of the piston whereby all pistonsmay be simultaneously reciprocated in the same direction to withdrawbarrels 25 and centers 26a from the finished workpieces and to move theminto engagement with unfinished workpieces after they have been loadedinto the lathe. This feature forms no part of our present invention. Fora more complete description thereof, reference is made to our copendingapplication, 447,810, filed June 20, 1942, of, which the presentapplication is a division.

Tailstock 4 (and this is true of tailstock also) is in the form of aunitary member or casting, rigidly attached to frame 2 of the machine.This form of tailstock, while very desirable from the point of rigidityand accuracy of the finished workpieces, presents problems in loadingwhich we have overcome in a novel manner by providing loading openings3| in said-tailstock housings between each of the uppermost andintermediate tailstocks, and openings 32 between each of theintermediate and lowermost tailstocks. Each opening is lined with asleeve 33 whereby dirt and chips are kept out of the hollow housings 4'and 5. In the case of the uppermost spindle, the workpiece issimplyloaded over the top surface 34, through the top chuck 9, into contactwith center 22. The intermediate spindle is loaded by inserting itsworkpiece through openinto contact with the adjacent ends of therespective workpieces, chucks 9 are closed in a conventional manner togrip the workpieces, and the lathe is then ready for operation. Afterthe workpieces have been finished, chucks 9 are opened, tailstockbarrels 26 and centers 26a are retracted by operation of pistons 28, andeach workpiece is tilted upwardly and slid to the left, Figure I,through an opening 3| or 32 or over top 34, as the case may be. andunloading a multiple-spindle lathe saves much time over the conventionalside-loading procedure heretofore used. Except for the slight tiltingmovement to insert and withdraw the workpieces from the open chucks,said workpieces have only an axial translatory motion from the time theyare moved up to the lathe until they ing 3| thence through chuck 9 andinto contact with center 23, and the lowermost spindle is loaded byinserting'its workpiece through opening 32, lowermost chuck 9 and intocontact with center 24. It will be noted, therefore, that theintermediate spindle of the lathe, for example, is loaded in thepreferred manner, by moving a workpiece adjacent the lathe tailstock 5so that it is parallel to the spindle axes of the lathe, and thereaftersliding it through opening 3|, tilting it downwardly to pass through thecenter opening of intermediate chuck 9 and finally giving it a combinedtranslation and tilt to bring it into coincidence with the axis of itsspindle and with one end in engagement'with tailstock center 23. Each oftheother spindles is loaded by a like movement, the only differencebeing that the uppermost spindle is loaded by moving the workpiece overthe top surface 34 instead of through an opening 3| or 32. After allspindles have been loaded in this manner, fluid under pressure isadmitted to cylinders 21 to axially move centers 26a are taken away. Theelimination of lost motion and consequent saving of time are obvious,while all lateral motion of the tailstocks and consequent complicatedmechanism for effecting such motion, are avoided.

Referring to Figure II, the frame 2 of the machine is formed withvertically extending dovetail .guideways 35 and 36. A tool relief member37 is guided for vertical sliding only in guideway 35 while a secondtool relief member 38 is similarly guided by guideway 36. Each member 3and '38 has a roller 39, mounted on a pin 40, as seen in Figure II. Aguideway 4| (Figure 111), is located along the top of frame 2 justbeneath rollers 39. A relief cam slide 4-2 is movable in guideway 4| andhas formed thereon relief cams 43 each supporting one of the rollers 39.Each cam consists of two horizontal dwells or flats, connected by aslope whereby, when the slide 42 is shifted from a position as shown inFigure II, to the right, rollers 39 ride down the slopes and permit toolrelief members 31 and 38 to move downwardly a definite limited distanceunder their own weight, as will be apparent from an inspection of FigureII. Relief cam slide 42 is shifted along its guideway by a cylinder 44fixed to frame 2 and having a piston and attached rod 45 fixed to saidmember. Control means not shown operates to admit fluid under pressureto, and exhaust it from, opposite ends of said cylinder 44, wherebyslide 42 is moved and the relief members raised and lowered at theproper times in the operating cycle of the machine for a purpose thatwill be explained subsequently.

Referring next to Figure VI, the tool relief member 31 has a dovetailchannel 46 therein extending at right angles to its own direction ofmotion in frame 2. Tool relief member 39 has a similar dovetail channel41 therein. The two channels 46 and 41 are aligned as shown in FigureVI, and a feeding slide 48 is slidably mounted in both of them.

A plate 49 is fixed to the feeding slide 48 by screws50. Said plateextends vertically and has attached thereto spaced tool blocks 5| eachof which carries a tool 52. The parts are so proportioned that each tool52 is properly located for operation On a workpiece in a respectivespindle when tool relief member 31 is raised by cam slide 42, andlowered out of contact with said workpiece when tool relief member 31 islowered by proper actuation of slide 42, as has been previouslydescribed. Feeding slide 48 also carries a second plate 54, rigidlyfixed thereto by screws 55. Plate 54 has spaced tool blocks 56 rigidlyattached thereto each carrying, for this particular job, a series oftools 51 for a purpose to be described. These tools, of course, aremovedThis manner of loading up and down toward and from their respectivespindle axes by tool relief member 31 synchronously, and to the sameextent as tools 52.

A feeding slide 53 is slidably mounted in the dovetail channel 41 oftool relief member 38. This feeding slide has a dovetail guideway 58therein parallel to the guideway 38 in which its tool relief member 38slides. A sliding bar member 59 is guided by this guideway. This membercarries spaced tool blocks 68 each of which has tapering tools 6|therein. Relief member 38 has a taper attachment bar 62 fixed thereto. Aguideway is formed in this bar with an aXis inclined at an angle to theaxes of the work spindles. This angle is determined by the taper of theportion of the workpiece to be operated upon. A shoe 63 slidably fitssaid guideway and has a hole fitting a pin 64 fixed to sliding barmember 59. By this construction, as feeding slide 53 is moved axially ofthe work, bar member 59 and its attached tool blocks 56 and tools 6|move axially to the same extent and they also move radially of thespindle axes whereby theproper tapering cut is effected upon theworkpieces.

Axial movement of feeding slides 48 and 53 is effected by mechanismincluding a box-shaped feeding slide 65 (Figures I to VI) mounted inguideways 56 formed in the top of tailstock housings 4 and 5. This slideis guided for movement parallel to the work spindle axes and has a rack61 on the rear inner wall of its lefthand end as viewed in Figure VI. A-shaft 68 is journaled in frame 2 of the machine and at its top carries apinion 59 meshing with rack 61, and, at its lower end, a pinion 10meshing with a rack formed in, or attached to, feeding slide 48. Saidslide 65, at its right hand end, as viewed in Figure VI, and on theinside of its forward wall, carries a second rack 12. A shaft 13 isjournaled on frame 2. This shaft has at its top, a pinion 14 meshingwith rack 12 and, adjacent its lower end, a pinion I5 meshing with arack 18 integral with, or attached to, feeding slide 53. By thisconstruction, as the box-shaped feeding slide 65, is actuated, pinions69, 14, 13, and I5, together with shafts 68 and 1'3 are turned, tothereby move slides 48 and 53 and the tool blocks and tools mountedthereon, in a direction parallel to the axes of the work spindles. Acylinder TI is secured to the top of frame 2 by bolts 18. Said cylinderhas connections, not shown, for controlling the admission and exhaust offluidunder pressure to the opposite sides of a piston therein. Saidpiston is attached to a piston rod 19. The outer end of said rod 19 isattached as at 80 to box-shaped feeding slide 65. Therefore, as pressureis admitted to one end or the other, of cylinder 11, slide 65 is movedand feeding slides 48 and 53 are simultaneously moved in oppositedirections axiallyof the work. It will be noted, too, that racks H and18 are made wider than their respective driven pinions ill and 15 sothat meshing engagement between these parts is maintained despitevertical movements of tool relief members 31 and 38, as previouslydescribed. It will also be noted that, for example, upper tool blocks5|, 5B, and 63 are in alignment axially of the work spindles. The sameis true for the corresponding intermediate tool blocks and for the lowertool blocks. Referring to Figure III, it is seen that all of theseblocks, such as 5|, mounted upon the same plate 49, are spacedvertically and form between them spaces or passageways. When tool reliefmembars 31 and 38 are in lowermost position, prior to the start of acutting cycle, these passageways are in substantial alignment withcorresponding tailstock openings 3| and 32, respectively, whereby free,unobstructed passageways are formed through which the workpieces may beloaded into the machine without loss of time and without danger ofinjury to the adjacent parts of the machine.

1 Facing tools 8| and 82 are carried in holders .83 and 84, as best seenin Figures I and III. Said holders are carried on respective rock shafts85 journaled in tailstock housings 4 and 5 to swing on axes parallel tothe work spindle axes so that the tools move in an arcuate path towardand from the work and in a plane normal to the work spindle axes. Theserock shafts are actuated in feeding and return movements by boxshapedfeeding member 65 by means of cams 86, Figure V, which are fixed toslide 65. Referring to Figure IV, it will be noted that rods 81 aremounted for vertical sliding movement, one in tailstock housing 4 andanother in tailstock housing 5. Each rod extends upwardly through anenlarged opening in the bottom of feeding slide 65 and carries, at itsupper end, a roller 88 riding on one of the cams 86. Each rod extendsdownwardly and terminates a little below the level of the lowermost rockshaft 85, and carries three slots, each slot being located opposite,that is to say, substantially in the same horizontal plane as, acorresponding rock shaft 85. Each rock shaft has a lever 9 fixed there-.to.v Each lever projects toward its actuating Operation Our lathe isillustrated, merely as an example, as working upon automobile axlesrequiring a cylindrical surfacing out near each end, a taper cutadjacent one end only, a chamfering cut at one end, and facing cuts toform a collar between the larger end of the taper and one finishedcylindrical surface. The axles are taken from a conveyor or truck (notshown) located at the right hand side of the machine, as viewed inFigure I, where they are positioned substantially parallel to thespindle axes. Each axle is slid off its support and (in the case of theintermediate and lower spindles), through opening 3| or 32, tiltedslightly downwardly to pass through the corresponding center chuck, thenleveled off until the turning opening in its leading end, fits over theleft hand tailstock center 23 or 24 as the case may be. After allspindles have "been loaded, fluid under pressure is admitted in theproper manner to cylinders 21, thus moving barrels 26 and centers 26ainto the turning holes in the right hand ends of the workpieces toprecisely position each workpiece in the machine. The center chucks arethen operated to clamp the workpieces. At the beginning of a work cyclerelief cams 43 are at their position farthest to the right, as viewed inFigure II, so that tool relief members 31 and 38 are in their lowermostposition and tools 52in blocks 5|, tools 51 in blocks 55 and taperintools 6| in blocks so are all in their lowermost 'position, out ofcontact with the work, likewise feeding slides 48 and 53 are in positionshown 'in Figure VI, with adjacent tools 51 and 765i axially separated"so asto outline between them, the desired collar on the work. Similarlyrock shafts are so positioned that their chamfering and facing toolholders 83, 84 are in their outermost position and tools 8i and 82carried thereby, are out of contact with the workpieces. As shown atFigure 111, the tools 52, 51, and 61 are so positioned as to engage thework at points directly underneath, while 'charnfering and facing tools8|, 82 are so positioned as to engage the work at points locatedinsubstantially horizontal planes through the spindle axes, and on theforward side of the workpieces.

Driving motor 20 is then started to rotate theworkpieces and fluidpressure is admitted to cylinder 44 to move piston rod 45 outwardly,translate relief cam slide 42 in its 'guideway, cause 11ollers 39 toride up the slopes of cams I3 and come to rest on the upper flats ofsaid cams to thus positively raise tool relief members 3-! and 38 invertical guided movement. This operation moves tools 52, 51 and '6! intothe workpieces to proper depth for the initial cuts. Thereafter, fluidunder pressure is admitted to cylinder -:11 in such manner as to drivebox-shaped feeding slide :65 to the left, as viewed at FigureVI. Thismovement simultaneously rotates shafts 158 and 73 and, through pinion 10and rack "H, in the case of feeding slide 38, and pinion l and rack:l'ii in the case of feeding slid 53, causes .said slides to moveaxiallyof the work in opposite directions. Tools 52 and 51 are thusmoved axially along their workpiece to effect the desired cylindricalcuts while tools '6! are, by reason of taper bar 62 and shoe 63, given amotion having simultaneous axial and radial components relatively to-the work, to effect the desired-taper cuts. At the same time, movementof slide 55 causes .downward movement of rods 81 to thereby rock'chamfering and facing tools 8!, 82 toward and into cutting contact withthe work. Precise control of fluid pressure admitted to cylinder l1enables traverse of the cutting tools at the proper rate for the workbeing done. The parts are so proportioned and adjusted that, when movement of'box-shaped slide 135 has been completed, all cuts are finished atone pass of the tools. Thereafter, how of pressure fluid to cylinder 44and 17 is reversed to first retract the tools from the work by loweringof relief members 37, 38 and then to move feeding' slides 48 and '53 toinitial position and simultaneously, to retract chamfering and facingtools iii, 82 from the work. The chucks are then opened and theworkpieces tilted upwardly and, slid to the left as viewed in Figure I.-In the'case of the intermediate and lowermost workpieces, theworkpieces are unloaded through'tailstock openlugs 31 and 32directlyonto an adjacent conveyor or truck.

It will thus be seen that we have provided a combination of elements ina lathe which results in precise but rapid finishin of the work and, atthe same time, effects smooth efficient, and time saving passage of thework through the machine, with all lost motion eliminated.

While, in order to comply with the patent statutes, we have described apreferred embodiment of our invention, operating upon a particular jobor workpiece, it will be understood that the machine is not so limited.On the contrary, it is readily adaptive to a large number of "turninjobs, while various substitutions and mechanical changes will beapparent to those skilled in this art. The invention extends to all suchuses, substitutions and equivalents, as fall within the scope of thesubjoined claims.

Having now described our invention, what we desire to claim and secureby U. S. Letters Patent 1. In a multiple spindle lathe, a frame, spacedstocks on said frame, a plurality of rotatable, su-

erposed spindles in each stock defining spaced, parallel, coplanar workaxes of rotation, there being passageways in each stock between adjacentspindles through which work pieces may be loaded into and unloaded from,said spindles, a tool relief slide movable on said frame normal to saidaxes, spaced tool blocks carried by slide, one for each work axis, eachtool block being coplanar with, but out of alignment with said axes,whereby unobstructed passageways are formed through which workpieces maybe loaded in an axial direction through either stock into the lathe.

2. In a multiple spindle lathe, a frame, spaced tailstock housings onsaid frame, a plurality of superposed tailstock barrels in eachtailstock housing, each barrel havingaxial movement only in its housing,there being aligned passageways in each housing between-adjacentbarrels, through which workpieces may be loaded into and unloaded fromsaid lathe in an axial direction, a

' vertically movable tool relief slide on said frame carrying spacedtool blocks, each block being normally below a line betweencorresponding passageways, and means for moving said slide tosimultaneously move said blocks upwardlyinto working position withrespect to their respective work axes. i Y

3. A multiple spindle lathe of the center drive type comprising, a base,spaced, parallel tailstock frames fixed to said base, a plurality ofvertically spaced barrels in each tailstock frame each adapted toreceive a tailstock center, the corresponding centers on opposite framesforming a pair, each-of said pairs of centers defining parallel workaxes, there being passageways in each tailstock frame between adjacentbarrels through which workpieces may be passed in an axial direction toload-said lathe, a' reliei frame supported by said base for verticalsliding movement normal to said work axes, a feedingframe carried bysaid relief frame for sliding movement parallel to said workaxes, aplate flxed to said feeding frame and extending normal to and offsetfrom said work axes, and vertically spaced tool blocks fixed to saidplate for holding toolsifor operation upon workpieces in the pairs ofcenters. respectively, the spaces between adjacent blocks being inalignment with a correspondin pair of passageways in opposite tailstockframes.

- 4. In a multiple spindle lathe, a base, .two tail-1 stock framesmounted on said base, a plurality of spaced spindles in each said frame,each spindle in one frame being aligned with a corresponding spindle inthe other frame to form a pair, said pairs defining spaced, paralleLsuperposed work axes of rotation, aheadstock on said said base formovement normal to said axes, whereby tools in said blocks may besimultaneously raised into cutting engagement with workpieces on saidcenters, the spaces between adjacent blocks being aligned withcorresponding passageways in said frames.

5. In a lathe, a frame, a plurality of spaced intergeared work spindlesrotatably mounted in said frame, a tailstock housing connected with saidframe, a plurality of tailstock barrels in said housing, each barrelaligned with a respective spindle to form a pair, said pairs definingspaced parallel and substantially coplanar work axes of rotation, meansmounting each barrel for axial sliding only in said housing, toolcarrier means, means mounting said carrier means for universaltranslation only, adjacent and parallel to the plane of said work axes,spaced tool blocks on said carrier means, each block being positionedbelow a respective work axis, and substantially in the plane of saidaxes, there being axially-extending openings in said housingintermediate each adjacent pair of barrels, each opening being alignedwith the space between a corresponding pair of adjacent tool blockswhereby to provide unobstructed loading passageways through whichworkpieces may be loaded in an axial direction through said tailstockinto the lathe.

6. In a multiple spindle lathe, a plurality of superposed intergeareddriving spindles, a tailstock housing, a plurality of superposedspindles in said housing, each aligned with a respective driving spindleto form spaced substantially co- Planar work axes of rotation, a toolblock carrier, means mounting said carrier for translation only in aplane offset from but parallel to, the plane of said work axes, spacedtool blocks on said carrier, each located adjacent 3, corresponding workaxis and in the plane thereof, there being openings in said housingbetween adjacent centers through which workpieces may be loaded in anaxial direction into said lathe, each opening being in substantial axialalignment with a corresponding space between adjacent tool blockswhereby unobstructed axially-extending loading passageways into saidlathe are provided.

'7. In a multiple spindle center drive lathe, a base, two spacedtailstock housings on said base, a

plurality of spaced barrels in each housing, each barrel being alignedwith a corresponding barrel in the other tailstock to form a pair, saidpairs defining spaced, coplanar work axes of rotation, a frame on saidbase between said housings, a plurality of intergeared work spindles onsaid frame, each aligned with a respective work axis, a plate meansparallel to and offset from the plane of said axes, means mounting saidplate means on said base for translation only parallel to said plane, aplurality of spaced tool blocks On said plate means, each block lying insaid plane immediately below a respective work axis, there beingopenings in each said housing between adiacent barrels, each openingbeing aligned with the space between corresponding adjacent tool blockswhereby workpieces may be'axially loaded through said openings into saidlathe.

8. In a lathe, a frame, a pair of spaced tailstock housings mounted onsaid frame, a plurality of centers in each housing, each centerdefining, with a corresponding center in the other housing, a work axisof rotation, all said axes being substantially parallel and lying in acommon plane, a plurality of center drive work spindles between saidhousings, each aligned with a respective work axis, means foractuatingsaid centers in an axial direction to engage work'- pieces, atool relief member translatable on said frame between idle and operatingpositions, in a direction normal to said axes, and in a plane parallelthereto, a feeding slide translatable on said member parallel to saidaxes, spaced tool blocks on said slide, each block being immediatelyadjacent a respective axi and lying substantially in the plane of saidaxes, power means for translating said member and blocks between idleand operating position, and power means for translating said slideaxially whereby tools in said blocks may operate upon workpieces in thelathe, there being openings in each housing between adjacent centers,each opening forming a pair with a corresponding opening in the otherhousing, each pair of openings being aligned with the correspondingspace between adjacent blocks when said member is in idle' position.

WILLIAM F. GROENE.

ARTHUR W. AUFDERHAR.

